Breakout Summary Report

ARM/ASR User and PI Meeting

2 - 6 May 2016

Session Title: Aerosol Measurements: Progress, Issues, and Needs
Session Date: 5 May 2016
Session Time: 8:30 AM - 10:30 AM
Number of Attendees: 0
Summary Authors: Jim Mather, Allison McComiskey, and Doug Sisterson

Breakout Description

The session was designed to initiate a discussion between the aerosol science community and the aerosol mentors and site operations staff to develop a common understanding of successes and problems from the science perspective on the one hand and operational progress and challenges on the other.

Main Discussion

Allison McComiskey started by providing some background to ARM aerosol measurements, including plans for core aerosol measurements desired at each of the ARM sites, while Jim highlighted the fact that resources are limited so we needed to work together to discover how ARM can best meet the science community’s measurement needs.

Larry Berg represented the science perspective by presenting results and experiences from TCAP. Scot Martin was also asked to present as the most recent PI for the MAOS instruments, but was unavailable for this session. Larry showed results from the TCAP campaign and seemed to be quite positive about the results, but he did have a few comments. He noted that regular consistency checks among instruments are needed and that there can be conflicts among instrument requirements (siting and internal temperatures [hot/cold]). He would like to see measurements of the coarse mode. Larry also indicated that short-term seasonal deployments of the composition measurements from MAOS were adequate, but that having a subset of measurements to provide context was useful.

Tom Watson provided a nice presentation of the issues associated with operating the ACSM, PILS, and PTRMS. He rated these in terms of their cost and operational complexity, with the PILS being less expensive than the other two but the most challenging to operate. The ACSM is more expensive and also operationally complex, requiring two highly trained staff for calibrations, which need to be done every ~3-6 months. The PTRMS is the most expensive of the aerosol instruments but is simpler to operate than the other two – at least when operating in a standard mode. Stephen Springston and Kim Nitschke followed Tom’s talk with additional background for instruments and site operations respectively. In Stephen’s presentation he noted that some measurements are not useful in some environments. For example, virtually no SO2 was observed in Brazil. He also noted that NOx is quite expensive and requires a separate inlet stack.

Following these presentations, there were several very useful contributions from the audience, which included a good mix of aerosol scientists and ARM infrastructure staff.

1) It was noted by a post-doc who had participated in GOAmazon through the operation of a guest instrument that she had never before experienced such great support for a field campaign. She was very pleased with the services provided by the AMF1 team. This was an encouraging affirmation of the services provided to PIs during field campaigns and underscores the value in facilitating guest instrument deployments.

2) Related to the above, it was noted in in a substantial suggestion as the session was breaking up that space for PIs to operate complex guest instruments in ARM shelters would be a good resource for investigators, and could alleviate costs to ARM while providing high-quality, detailed, and much desired measurements to the community. This space could take the form of a duplicate, empty AOS shelter to be filled with proposed guest instruments from any source.

3) Peter McMurray noted that it is difficult for scientists to provide useful feedback to ARM regarding priorities without knowing the operational costs and overall constraints. With this information, the community could better decide what set of measurements would best suit the needs of a given set of science goals.

4) It was suggested that it would be beneficial to have an SMPS dedicated to calibration with each AOS. This would serve both ACSM and CCN calibrations and would mitigate some of the logistical difficulties and cost of having one roaming instrument. Further, if the calibration process could be automated and/or performed by onsite technicians, the resources required for calibration would be much reduced.

5) It was also noted that complex continuous online sensors are not the only path to obtaining aerosol composition measurements, which tend to be the most expensive and challenging to operate in the field. Aerosol filters provide another mechanism to obtain this information. These are much simpler to operate in the field, though not without their own drawbacks – they provide very coarse temporal resolution and analyzing the filters is costly. On the other hand, there are examples of operational filter networks from which ARM could draw recommendations for best practices to get off to a smooth start with filter operations (esp. the IMPROVE network).

6) There was a request not to lose sight of lidars and UAS as a method of obtaining information about vertical profiles of aerosol properties. There was a suggestion that ARM MPLs may not be used to their full potential

7) Make use of SBIR as a mechanism to improve measurements or fill measurement gaps.

8) While much of the session was focused on measurements, it was noted that Value-Added Products (VAPs) should also be considered in terms of their potential benefit (as well as their cost).

Action Items

1) The most compelling take-away from the session was the suggestion to clearly define the cost of operating these instruments and present constrained options with costs to the user community for further input. A similar message came out of the User Executive Committee in our face-to-face meeting a month earlier (applied more broadly). A key action item, then, is to determine the operational cost of each of the AOS/MAOS instruments and build a matrix of capability (what the instrument can provide) and cost (what it takes to operate) – and then solicit further information based on this information.

2) Include optical measurements and include the information from and operational costs of filter-based composition measurements in the above report, although the latter would be new measurements for ARM.

3) Based on the input from workshop reports from the past year and input from other sessions at the ASR/ARM meeting – identify possibly candidates for instrument development/maturation and review options for pursuing that development including SBIR.

4) Identify an appropriate time/setting to have a follow-on discussion to this session once we have completed the above actions.